Functional analysis of the conserved transcriptional regulator CfWor1 in Cladosporium fulvum reveals diverse roles in the virulence of plant pathogenic fungi

Bilal Okmen, Jerome Collemare, Scott Griffiths, Ate van der Burgt, Russell Cox, Pierre J. G. M. de Wit*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

21 Citations (Scopus)

Abstract

Fungal Wor1-like proteins are conserved transcriptional regulators that are reported to regulate the virulence of several plant pathogenic fungi by affecting the expression of virulence genes. Here, we report the functional analysis of CfWor1, the homologue of Wor1 in Cladosporium fulvum. cfwor1 mutants produce sclerotium-like structures and rough hyphae, which are covered with a black extracellular matrix. These mutants do not sporulate and are no longer virulent on tomato. A CE.CfWor1 transformant that constitutively expresses CfWor1 produces fewer spores with altered morphology and is also reduced in virulence. RNA-seq and RT-qrtPCR analyses suggest that reduced virulence of cfwor1 mutants is due to global downregulation of transcription, translation and mitochondrial respiratory chain. The reduced virulence of the CE.CfWor1 transformant is likely due to downregulation of effector genes. Complementation of a non-virulent fosge1 (Wor1-homologue) mutant of Fusarium oxysporum f. sp. lycopersici with CfWor1 restored expression of the SIX effector genes in this fungus, but not its virulence. Chimeric proteins of CfWor1/FoSge1 also only partially restored defects of the fosge1 mutant, suggesting that these transcriptional regulators have functionally diverged. Altogether, our results suggest that CfWor1 primarily regulates development of C.fulvum, which indirectly affects the expression of a subset of virulence genes.

Original languageEnglish
Pages (from-to)10-27
Number of pages18
JournalMolecular Microbiology
Volume92
Issue number1
DOIs
Publication statusPublished - Apr 2014

Keywords

  • AVIRULENCE GENE AVR9
  • DNA-BINDING DOMAINS
  • CANDIDA-ALBICANS
  • ALTERNARIA-BRASSICICOLA
  • MAGNAPORTHE-GRISEA
  • MASTER REGULATOR
  • EXPRESSION
  • TOMATO
  • FAMILY
  • PENETRATION

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